Effect of olive oil mill wastewater on extracellular ligninolytic enzymes produced by<i>Phanerochaete flavido-alba</i>

Abstract

Our previous results have demonstrated that Phanerochaete flavido-alba decoloration, dephenolization and detoxification of olive oil mill wastewater (OMW) were associated with changes in the ligninolytic major exoenzymes accumulated in the cultures. This paper describes the effect of the two main OMW components (monomeric aromatic compounds and a major brownish polymeric pigment), on extracellular P. flavido-alba ligninolytic enzymes. Laccase was the sole ligninolytic enzyme detected in cultures containing monomeric aromatic compounds. Laccase and an acidic manganese-dependent peroxidase (MnPA, pI<2.8) were accumulated in cultures with OMW or polymeric pigment. Also, modified manganese-dependent peroxidases were observed mainly in OMW-supplemented cultures. Laccase was more stable to the effect of OMW toxic components and was accumulated in monomeric aromatic-supplemented cultures, suggesting a more important role than manganese-dependent peroxidases in OMW detoxification. Alternatively, MnPA accumulated in cultures containing the polymeric pigment seems to be more essential than laccase for degradation of this recalcitrant macromolecule by P. flavido-alba.